A STRIP OF NEEDLES, IN PARTICULAR A TOP COMB FOR A TEXTILE MACHINE

Abstract

The invention relates to a strip of needles (22), in particular a top comb (12), for a textile machine with a number of needles (24) situated adjacent to one another, as seen in the longitudinal direction of the strip of needles (22), by forming free pass-throughs (0, 01) between the needles. It has been seen in practice that the drawing in of the edge zones (R) of the lap end (E) into the strip of needles (22) is more difficult. It is therefore proposed that the strip of needles (22), as seen in the longitudinal direction (L), is provided with at least one partial zone (T1, T2) which is provided with a different needle setting as compared to the remaining zone (B). FIG 3

Full Text

The invention relates to a strip of needles, in particular on a top comb of a textile machine with a number of needles situated adjacent to one another, as seen in the longitudinal direction of the strip of needles, by forming free pass-throughs between the needles. The strip of needles can also be arranged from at least two rows of needles disposed behind one another.
In the combing machine as is described in EP-A1-619 38 9 for example, the detaching process of the combed fibre tuft is made at a time when the nipper is located in the most forward and opened position. In this stage the nipper has the smallest distance from the nip point of the detaching cylinders which are provided downstream. The combed lap end projecting from the nipper is placed in this position on the fibre fleece end, which is conveyed back by the detaching cylinders by means of a reversing movement. Thereafter it is transferred to the nip point of the detaching cylinders by the initiated forward movement of the detaching cylinders - This leads to an overlap or a "piecing" of the two ends. As a result of the further forward movement of the detaching cylinders the fibres which are not retained by the lap or by the nipper unit are drawn off. During the conveying process of the lap end to the nip point between the detaching cylinder and during the actual detaching process the lap end arrives between the needles of the top comb which is attached to the nipper unit. The fibres which are drawn off by the detaching cylinders are thereby pulled through the strip of needles of the top comb, with neps, trash particles and other impurities being retained in particular.

As is also shown in particular from EP-Al 619 389, it is advantageous if the strip of needles of the top comb is cleaned frequently in order to facilitate and help the piercing of the needles into the fibre fleece.
It has been seen that particularly the edge zones of the detached fibre fleece are not pulled through the strip of needles of the top comb in an optimal manner. The consequence of this is that on the one hand said edge zones still contain impurities and that on the other hand soiled fleece edges are obtained.
Whereas the fibres in the central zone of the fleece to be drawn off can rest on either side on adjacent fibres, fibres located on the edge can only rest on one side on the fibres situated on the inside. The consequence of this is that the fibres in the edge zone give considerably less resistance against downward yielding during the piercing process of the strip of needles than is the case in the central zone of the fleece. This may lead to the effect that the central zone of the fibre fleece is drawn completely into the strip of needles, whereas the edge fibres reach the effective area of the needles of the needle strip only partially or not at all. Various efforts have therefore been made in practice to eliminate such disadvantages by attaching additional guide means, air supports, etc. The solutions thus proposed were either not satisfactory or too complex and thus too expensive.
The invention now has the object of arranging the strip of needles in such a way that the thus outlined disadvantages are avoided and there can be a near complete grasping of the fibre fleece through the strip of needles.

This object is achieved in such a way that the strip of needles, as seen in its longitudinal direction, is provided with at least a partial zone which is provided with a different needle setting as compared to the other area. Preferably, the arrangement and/or layout of the needles of the strip of needles is such that the free pass-throughs between the needles in the partial zone are partly enlarged as compared to the needles of the remaining area.
This also allows the pulling of those zones of the fibre fleece to be drawn off, which are also known as lap end or fibre tuft, into the strip of needles which give less resistance to the strip of needles during the piercing process. This relates in particular to the edge zones of the fibre fleece or of the fibre tuft to be drawn of f. The term "needles" is not be understood in a manner as limited to common needles with respective cross sections, but instead relates to needles which are produced as clothing, punched or stamped elements. If clothing tips are used as needles then it is possible to have different shapes of needles in numerous variations depending on the type of application.
It is proposed further that the needles in the partial zone have an altered needle geometry as compared to the needles in the remaining zone. The term "geometry" relates substantially to the shape of the needles, e.g. to the geometry of the bend-offs or the angle of attack or to the positioning with respect to the strip of needles. This means that the needles can be disposed or arranged in the partial zones in a respective manner so as to allow the easier penetration of the fibre fleece between the needles.

In order to reduce the resistance against the penetration in a certain partial area of the strip of needles it is further proposed that the cross sections of at least a part of the needles in the partial zone are different from the cross sections of the needles in the other zones (with the same number of needles per unit of length). The cross sections of these needles can be provided with a smaller cross-sectional area and thus cause an enlargement of the pass-throughs.
The provision of larger free pass-throughs benefits the penetration of the fibres in the strip of needles. The combing effect in this partial zone is slightly reduced as compared to the other zones owing to the larger pass-throughs. This slight disadvantage, however, is accepted, as otherwise there would not be any combing at all in this zone without a respective arrangement of the needles in this partial zone.
As a further embodiment it is proposed that the free pass-throughs between the needles of the partial zone are larger at least in the tip zone of the needles than in the other zone. This embodiment facilitates the first piercing of the needle tips into the fibre fleece and forms the basis for the subsequent complete draw™in into the strip of needles.
The further proposal in that the number of the needles in the partial zone is smaller per unit of length than in the other zone allows the use of the same needles over the entire length of the strip of needles and, at the same time, the described facilitated penetration effect in this partial zone -
If strips of needles, as seen transversally to the longitudinal direction of the strip of needles, are arranged in two rows of needles which are disposed

behind one another, an embodiment is proposed where in a partial zone the needles of at least one of the rows of needles is provided with a different kind of needle setting as compared to the other zone. One partial zone of the row of needles is preferably selected for this altered embodiment which pierces the fibre fleece first.
Said partial zone can be equipped with a number of needles per unit of length which is reduced as compared to the remaining zone. Another possibility is entirely omitting the needles of a row of needles in the selected partial zone.
It is proposed further that concerning the piercing direction, the tips of the needles in the partial zone are offset back at least partly as compared to the needles in the remaining zone. This means that the tips of the needles of the partial zone arrive with a delay in the zone of the fibre fleece with respect to the piercing process of the needles in the remaining zone. This benefits the drawing-in process of the fleece in this partial zone.
In order to reduce the friction between the needles and the fibres of the fibre fleece to be drawn into the strip of needles, it is proposed to provide the needles in the partial zone, as seen in the conveying direction of the fibre fleece, with a narrower arrangement as compared to the other needles. This facilitates the penetration of the fibre fleece in this partial zone.
As was already previously indicated, the problems described above occur substantially in the edge zone of the fleece or fibre tuft to be drawn of f. It is therefore proposed that, as seen in the longitudinal direction of the strip of needles, a partial zone with

a needle setting that is different in respect ot tne remaining zone, extends from the ends of the needle strip in the direction towards the centre of the needle strip.
The partial zones can have a length of between 5 and 15 % of the entire length of the strip of needles.
Usually, the outer fleece edge of the fibre fleece does not overlap with the outer edge of the strip of needles, but there is a safety margin between the edges in order to ensure a complete draw-in of the fibre fleece through the strip of needles. As a rule, this safety margin is kept small.
In order to facilitate the draw-in process of the fibre fleece in the partial zone it is further proposed that said partial zone is assigned an air source by means of which an air flow is produced against the piercing direction of the strip of needles.
Depending on the positioning towards the strip of needles, the air source can consist of a compressed air source or a suction unit.
Further advantages and embodiments are shown in the following description and the embodiments, wherein:
Fig. 1 shows a schematic partial view of a nipper unit of a combing machine with a top comb during the detaching process;
Fig. 2 shows an enlarged partial view of the top comb according to fig. 1 in the zone of the strip of needles;

Fig - 3 shows a top view Y according to fig 2 of a needle strip arranged in accordance with the invention;
Fig. 4 shows a top view Y according to fig. 2 with a further embodiment of a strip of needles arranged in accordance with the invention;
Fig. 5 shows a schematic representation of a strip of needles as arranged in accordance with the invention in a view X according to fig. 2;
Fig. 6 shows a further embodiment arrangement in accordance with the invention in a view according to fig. 2;
Fig. 7 shows a view XI according to fig. 6;
Fig, 8 shows a view according to fig. 3 with two rows of needles disposed behind one another;
Fig. 9 shows a view according to fig. 2 with a further embodiment with two rows of needles disposed behind one another and
Fig. 10 shows a view X2 according to fig. 9.
Fig. 1 shows a nipper unit 1 which consists of a top nipper 2 and a bottom nipper 3. As is generally known, the nipper unit 1 is held swivellably by swivelling levers (not shown) and performs a reciprocating movement during the nip of the comb. In the shown front position of the nipper unit the nipper plate 4 of the top nipper 3 is lifted from the nipper plate 5 of the bottom nipper 2. The top nipper 3 is held swivellably movable about a schematically shown swivel point 7 on the bottom nipper 2.

A feed cylinder 9 is also rotatably held in the bottom nipper 3. It unwinds a web W, referred to herein as a lap which is unwound from a lap roll (not shown) , and is supplied to a nipper mouth M. The movement of the feed cylinder 9 occurs intermittently via a ratchet drive (not shown) by the swivelling movement of the top nipper 3. The amount of feed of the feed cylinder 9 which is performed during each nip of the comb in the forward motion or backward motion of the nipper unit 1 is usually between 4 mm and 5 mm and is adjustable. A top comb 12, which is attached to the bottom nipper 2, is arranged between the path of movement of the nipper plate 4 and the detaching cylinders 14, 15 which are provided downstream. The detaching cylinders 14, 15 are connected with a drive (not shown) which allows a pilgrim-step movement of the detaching cylinders - This, however, is general state of the art and shall not be described here in closer detail.
In the shown example, the top comb 12 consists of a top comb holder 18 to which a plate 20 is attached by way of a screwed connection 19. A strip of needles 22 is attached to the lower end of plate 20. This is also shown in particular in the enlarged representation according to fig. 2. The strip of needles 22 is formed by needles 2 4 which are situated mutually adjacent and between whom a spacer element 25 is attached. This will be explained below in closer detail by reference to the following embodiments.
The needles as well as the spacer elements can connected either mutually or with the plate 20 by way of a glued or soldered connection for example. Other embodiments are possible and are also well known from the state of the art.

As is further shown in fig. 1, the lap end E (also known as fibre fleece or fibre tuft) projects from the opened nipper mouth M and rests on the end of the previously formed fibre fleece V. The strip of needles 22 pierces the lap end E. The lap end E was previously combed out by a circular comb segment (not shown). The nipper unit 1 was in the closed and rear position during the combing process. During the further movement of the detaching cylinder 14, 15 the lap end E reaches the zone of the nip point K, as a result of which the actual detaching process commences. The fibres are pulled out of the lap W by the detaching cylinders 14, 15 which on the one hand have been grasped by the nip point K and on the other hand are not held back by the retaining force of the lap or the nip force by the feed cylinders 9 in the nipper unit 1. During this detaching process the detached fibres are pulled between the needles 2 4 of the strip of needles 22. On the one hand, any impurities such as neps, trash particles, dirt, etc. located between the fibres are held back in this way or by the top comb. These impurities are then grasped during the next following combing process by the circular comb segment and are discharged downwardly for disposal. The lap end faces downwardly during the combing process of the lap end E through the circular comb segment. During the forward movement of the nipper, which opens in this process, the combed end E is bent slightly upwardly owing to the inner restraining power and meets the end of the fibre fleece V which has been fed back by the detaching cylinders 14, 15. As soon as the detaching cylinders 14, 15 move in the forward direction again, the lap end E is entrained by the end of fleece V upwardly in the direction towards the nip point K. During this movement the lap end E arrives between the needles of the strip of needles 22. In order to also enable the edge zones of the lap end E to reach the strip of needles during

this process and to prevent them from yielding, the outer partial zones Tl, T2 of the strip of needles were arranged in accordance with the invention with an altered needle setting. This is shown in particular in the examples of the following figures from fig. 3. In order to facilitate the penetration of the edge zones R of the lap end E with the width VI into the strip of needles 22 the number of needles 2 4, as regarded per unit of length, was reduced as compared to the middle zone B. In the shown example according to fig. 3 the needles 2 4 are shown schematically as lines. The strip of needles is provided with a length L which projects with a distance P beyond the fleece edge R of the lap end. The distance P is chosen as a safety margin so as to ensure a complete coverage of the width VI of the lap end E. The representation shows that in the zone B, relating to the same unit of length, there are twice the number of needles than in the partial zones Tl or T2. This facilitates the penetration of the edge zones R into the partial zones Tl, T2 and thus allows that these zones are also combed through. The yielding of the edge zones R downwardly from the zone of the strip of needles is thus counteracted.
Fig. 4 shows a further embodiment, with needles 27 being shown in a partial zone Tl and needles 28 in the remaining zone B. The needles 27 are provided with a smaller cross-sectional area than the needles 28. As in this example the same number of needles is located in both zones (Tl, B) per unit of length, different free pass-throughs D or Dl arise between the needles. This means that the pass-throughs Dl in the partial zone Tl are larger than the pass-throughs D in the remaining zone B. This leads to the consequence that a penetration of the fibres in the edge zone of the lap end is easier in the partial zone Tl than in the remaining zone B.

Fig. 5 shows a further embodiment. In the partial zone Tl the needles 30 taper downwardly more strongly than the needles 31. The result of this is that the distance of the tips Si of the needles 30 is larger in the zone Tl than the distance of the tips S between the needles 31 in the remaining zone B, which thus allows an easier piercing of the fibre fleece. In order to obtain a respectively desired free passage between the needles, spacer elements 25 are attached between the needles . In this example too, the number of needles per unit of length is kept the same in the partial zone Tl as well as in the remaining zone B.
Figs. 6 and 7 show a further embodiment, with the needles 33 in the partial zone Tl having a shorter length as compared to the needles 3 4 in the remaining zone B. The spacer elements 25 as described above are attached between the needles. This means that the needle tips 35 of the needles 33 are offset backwardly by the amount Nl towards the tips of needles 34 with respect to the piercing direction N. This arrangement also allows an easier penetration of the outer edge fibres of the lap end E. In order to reduce the contact surface and thus the frictional force during the penetration into the lap, the needles 33 are additionally arranged narrower in the combing zone than the needles 34.
Fig. 8 shows a further embodiment, with the strip of needles being formed of two rows of needles 38 and 39. The forward needle row 39 is arranged similarly over all zones Tl, B, T2 with respect to the arrangement of the needles and the design. The needles of the rear needle row 38, on the other hand, are arranged differently in the outer edge zones Tl and T2. An embodiment is shown in zone Tl where fewer needles 24

are present per unit of length than in the remaining zone B.
The attachment of needles 24 was omitted entirely in the zone T2. On the one hand, this facilitates the penetration in the zones Tl, T2 of the edge zones of the lap end E and, on the other hand, a combing effect which is still adequate is achieved- The zones Tl and T2 of the row of needle 38 are naturally arranged in a similar way.
Figs. 9 and 10 show a further embodiment with a double row of needles according to fig- 8, with needles 42 and 43 being produced as a punched or stamped element or as a clothing element. During the production from a clothing element, it is possible to cut the individual double needles 42 and 43 into lengths from a clothing strip. The double needles are pushed onto a holding rod 4 4 by attaching spacer elements 25 and are attached in a respective manner (not shown) - In the outer zone Tl or T2 the rearwardly facing needle tip 41 (with respect to the conveying direction F) is arranged shorter and narrower - This also facilitates the penetration of the lap end in the edge zone R into said double strip of needles.
As is shown in particular in fig. 5, the drawing of the lap end into the strip of needles can be supported in the partial zones by producing an air flow 51 in the direction towards the tips of the needles. As is shown, this air stream can be produced by a compressed air nozzle 50. It is also possible to attach a suction nozzle (not shown) above the strip of needles in the respective partial zone in order to produce the air flow 51.

The activation of an air flow 51 can be used in addition in all embodiments and must be time-controlled according to or synchronised with the course of the nip of the comb. The control could be based on the scanning of the rotational angle of the circular comb axle for example, Devices on the circular comb could be used for providing the air flow as have been described in DE-A1-195 040 10 for example.
Numerous other embodiments and variations are possible to arrange and provide the needles in the partial zones Tl and T2 in the respective way so as to allow the easier drawing in of the edge zone R of the lap end E into the strip of needles.

CLAIMS:
1. A strip of needles (22) , in particular a top comb
(12) , for a textile machine with a number of needles (24) situated adjacent to one another, as seen in the longitudinal direction of the strip of needles (22), by forming free pass-throughs (D, Dl) between the needles (24) , characterized in that the strip of needles (22) , as seen in its longitudinal direction (L) , is provided with at least one partial zone (Tl, T2) which is provided with a different needle setting as compared to the other area (B).
2. A strip of needles (22) as claimed in claim 1,
characterized in that arrangement and/or layout of
the needles (27, 28, 30, 31, 33, 34, 41, 42, 43)
of the strip of needles (22) in the partial zone
(Tl, T2) is made in such a way that the free pass-
throughs (D, Dl) between the needles in the
partial zone (Tl, T2) are at least partly enlarged
as compared to the needles of the remaining area
(B) .
3. A strip of needles (22) as claimed in one of the claims 1 or 2, characterized in that the needles in the partial zone (Tl, T2) have an altered needle geometry as compared to the needles in the remaining zone (B) .
4. A strip of needles (22) as claimed in one of the claims 1 to 3, characterized in that the cross sections of at least a number of the needles (27) in the partial zone (Tl, T2) are different from

the cross sections of the needles (2 8) in the remaining zone (B).
5. A strip of needles (22) as claimed in one of the claims 1 to 4, characterized in that the free pass-throughs (SI) between the needles (30) of the partial zone (Tl, T2) are larger at least in the tip region of the needles than in the remaining zone (B).
6. A strip of needles (22) as claimed in one of the preceding claims, characterized in that the number of needles (24) in the partial zone (Tl, T2) is smaller per length of unit than in the remaining zone (B).
7. A strip of needles (22) as claimed in claim 1 with at least two rows of needles (38, 39) which are, as seen transversally to the longitudinal direction of the strip of needles, disposed behind one another, characterized in that at least one of the rows of needles (38) is provided with a partial zone (Tl, T2) which is provided with a different needle setting as compared to the remaining zone (B).
8. A strip of needles (22) as claimed in claim 7, characterized in that in the partial zone (Tl, T2) the number of needles per unit of length is reduced in at least one of the two rows of needles (38, 39) as compared with the remaining zone (B) or that the needles (24) are omitted entirely.
9. A strip of needles (22) as claimed in one of the preceding claims, characterized in that at least partly the tips (35, 41) of the needles (33, 42) in the partial zone (Tl, T2) are offset back with

respect to the piercing direction (N) as compared to the needles (34, 43) in the remaining zone.
10. A strip of needles (22) as claimed in one of the preceding claims, characterized in that the needles (33, 42) in the partial zone (Tl, T2) are arranged, as seen in the conveying direction (F) of the fibre fleece (E), at least partly narrower as compared to the needles (34, 43) in the remaining zone.
11. A strip of needles (22) as claimed in one of the preceding claims, characterized in that, as seen in the longitudinal direction of the strip of needles (22) , a partial zone (Tl, T2) with a different needle setting as compared with the remaining zone (B) extends from the ends of the strip of needles (22) in the direction towards the centre.
12. A strip of needles (22) as claimed in one of the preceding claims, characterized in that the length of the partial zones (Tl, T2) is between 5 and 15 % of the entire length (L) of the strip of needles.
13. A strip of needles (22) as claimed in one of the preceding claims, characterized in that in the zone of the partial zones (Tl, T2) an air source (50) is arranged which produces an air flow (51) in the direction towards the needle tips against the piercing direction (N) .

14. A strip of needles of a textile machine substantially as herein described with reference to the accompanying drawings.